<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <div id="app">
      {{ message }}-{{arr}}
      <button @click="addItem">Add Item</button>
    </div>
    <script src="./vue/vue3.5.13.js"></script>
    <script>
      const { createApp, watch, ref } = Vue;
      const arr = ref(["123"]);
      console.log(arr);
      createApp({
        setup() {
          const message = ref("Hello vue!");
          const addItem = () => {
            console.log(123123);
            arr.value.push('444')
          }
          watch(arr,()=>{
            console.log(111);
            
          },{deep:true})
          return {
            message,
            addItem,
            arr
          };
        },
      }).mount("#app");
    </script>
  </body>
</html>
